Microminiature lamp assemblies



Fild May 1,1967

p 1969 c. w. MARTIN 3,465,197

MICROMINIATURE LAMP ASSEMBLIES 2 Sheets-Sheet 1 v IN VENTOIQ. CHARLES"(Mme T/N Mm z/m/ IOTTOQNEHY.

Sept. 2, 1969 c. w. MARTIN MICROMINIATURE LAMP ASSEMBLIES 2 Sheets-Sheet2 Filed May 1, 1967 f N vEN TOE CuneL 55 W: M02 T/N United States PatentO M 3,465,197 MICROMINIATURE LAMP ASSEMBLIES Charles W. Martin,Placentia, Calif., assignor to Opcalite, Inc., Santa Ana, Califi, acorporation of Delaware Filed May 1, 1967, Ser. No. 635,228 Int. Cl.H01j /50 US. Cl. 313-318 8 Claims ABSTRACT OF THE DISCLOSUREMicrominiature lamps formed with an envelope containing an illuminatingfilament electrically connected by a pair of filament wires to a pair ofpin connectors of the type which are comprised of a group of spiralwound wire strands which resiliently compress to provide a tensioned fitwithin mating electrical contact sockets. A collar surrounds thefilament wires and is overlappingly attached to the interconnectedportions of the envelope and the pin connectors.

BACKGROUND OF THE INVENTION This invention relates to illuminating lampassemblies, and more particularly to microminiature lamp assemblieshaving twisted wire pin connectors especially adapted for utilization inprinted circuit boards and the like.

Prior to this invention microminiature lamp assemblies, such as werecommonly used in conjunction with printed circuit boards, were notreadily removable from the boards. Generally, the need for secureattachment to maintain uninterrupted electrical contact when subjectedto vibration necessitated a relatively permanent attachment of the lampassemblies to the board. Thus, replacement of the lamp assembliesrequired cutting of the connectors and attachment of the new lampassemblies by such time-consuming methods as soldering. Moreover, thelamp assembly units were often not interchangeable so that a number ofdifierent types of replacement units were required.

Although microminiature lamp assemblies having quickly detachable pinand socket type electrical connectors were considered desirable, thesacrifice involved in size, weight and reliability using conventionalconnectors was too great to render their utilization practical. Tounderstand the problems involved, the extremely small size ofmicrominiature electrical components should be appreciated. Thus,generally speaking, microminiature components can be categorized byreference to the size of their socket contacts as those which are .031inch or less in diameter.

Conventional pin and socket type' connectors require substantial spaceand weight allowances that decrease the advantages of utilizingmicrominiature lamps. In addition, they are not capable of solving thecritical design problems presented by microminiaturization ofmaintaining electrical contact within a small surface area whileproviding positive electrical connection during vibration and shockcondition.

SUMMARY OF THE INVENTION Therefore, it is a primary object of thisinvention to provide a lamp assembly, suitable for utilization withprinted circuits, which is readily replaceable, interchangeable, andsecurely connected to provide uninterrupted electrical contact underadverse environmental conditions.

Patented Sept. 2, 1969 A microminiature lamp assembly, in accordancewith the objectives of this invention, includes a sealed illuminatingenvelope within which is contained a light-emitting filament that iselectrically connected to twisted pin type base contact members. A groupof helically wound strands of wire comprises the outer periphery of thecontact members which are adapted to be inserted in complementarysockets or plated through holes of a printed circuit board so as toresiliently engage the interior walls thereof, and thereby eliminatedisengagement induced by vibrational stress.

Another advantage of this assembly is that it may be used with circuitboards of different thickness depending upon application.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a perspective view of avertical-type microminiature lamp in accordance with this invention.

FIGURE 2 is a perspective view of a microminiature lamp, as in FIGURE 1,inserted in operative position in a printed circuit board.

FIGURE 3 is an exploded perspective view of the separated components ofa microminiature lamp, as shown in FIGURE 1.

FIGURE 4 is an enlarged, vertically sectioned view of a microminiaturelamp inserted in a printed circuit board, taken through 44 in FIGURE 2.

FIGURE 5 is a cross-sectional view of a microminiature lamp takenthrough 55 in FIGURE 4.

FIGURE 6 is a vertically sectioned view of a pair of vertical typemicrominiature lamps which have a common collar assembly.

FIGURE 7 is a fragmented top plan view of two pairs of horizontal typemicrominiature lamps in accordance with this invention, disposed in thecorners of an annunciator assembly utilizing a printed circuit board.

FIGURE 8 is a sectioned view of the microminiature lamps and annunciatorpanel taken through 88 in FIG- URE 7.

FIGURE 9 is a partly sectioned, top plan view of another horizontal typemicrominiature lamp inserted in a printed circuit board.

FIGURE 10 is a cross-sectional view taken through 1010 in FIGURE 9 ofthe microminiature lamp and portion of the printed circuit board withinwhich it is mounted.

DESCRIPTION OF THE PREFERRED EMBODIMENT A single bulb microminiaturelamp assembly embodying a vertical type form of this invention isillustrated in FIGURES 1-5. Basically, as best viewed in FIGURE 3, thelamp assembly is comprised of a sealed, transparent or at leasttranslucentcylindrically elongated illumination envelope 10, which isbulb-shaped at its free end and contains a partly curled, slender,wire-type, light emitting filament 12 within it. Two spaced portions offilament wires 12a and 12b, extending from and supporting the oppositesides of filament 12, protrude through the somewhat flattened end of theenvelope 10, which is opposite from the bulb-shaped end thereof. Such anassembly is known as an incandescent miniature lamp. After extending ashort distance exterior of envelope 10, the wires are attached bysoldering or other means to spaced, axially parallel, elongated, twistedpin connectors 14 and 16, respectively. The size of this envelope isabout .096 inch in diameter, and about .210 inch long.

Pin connectors 14 and 16 are preferably of the type which are comprisedof seven strands of .005 inch diameter spring copper wire woundhelically around a copper core of three strands of .0035 inch diametersoft copper wire. Such a connector bulges centrally to about .025 inchin diameter and terminates in a smaller rounded end. It is substantiallyaxially rigid, though it can be resiliently compressed in diameter.

Surrounding the portions of the Wires 12a and 12b that extend betweenthe envelope 10 and the attached connectors 14 and 16 are rigid, hollow,cylindrical sleeves 18 and 20, respectively. These sleeves are slightlylarger in internal diameter than the adjacent portion of the connectors14 and 16. Moreover, they are preferably long enough to extend fromadjacent the envelope 10 to slightly overlap the connectors 14 and 16 towhich they are secured by circumferentially indented gripping crimps 18aand 20a, respectively.

A hollow, cylindrically shaped collar 22 overlappingly extends from andencompasses the connected end portion of the envelope 10, surroundsentirely the sleeves 18 and 20, and terminates surrounding the attachedend portions of the connectors 14 and 16. This collar 22 serves as aninsulator, lamp mounting structure and spacer for the lamp assemblywhich, as shown, is about .260 inch long. The internal shape of collar22 is formed to conform with the external configuration of the portionof the lamp assembly which it encompasses. It is secured in place by theapplication of a clear, transparent, sealant type potting compoundbetween its internal surfaces and the external surfaces of the adjacentcomponents of the lamp assembly. Thus, as shown in FIGURE 4, the collar22 is formed with a cylindrical cavity 22a conforming to and receivingthe connected end portion of envelope 10. Communicatingt herewith and inaxial alignment with said cavity 22a are parallel elongated bores 23 and24 to receive sleeves 18 and 20 respectively. Also the collar 22includes two generally parallel bores 23a and 24a of reduced size whichextend from the end 31 of the collar 32 and communicate with bores 23and 24. Because of the reduced diameter of the bores 23a and 24ashoulders 23b and 24b are formed at the bottom of bores 23 and 24, whichact as stops for the sleeves 18 and 20.

The lamp assembly is intended to be inserted into the circuit of aprinted circuit board 25. Thus, a printed circuit 26 in board 25incorporates a pair of plated through holes 28 and 30 which act aselectrical sockets and are slightly smaller in diameter than the pinconnectors 14 and 16. These holes 28 and 30 have the same relativespacing as the pin assembly 14 and 16 in order to provide continuouselectrical contact with the circuit 26. The interior plating of thesockets is with an electrically conductive material which provides anuninterrupted continuation of the printed circuit 26 therein. Theinterchangeability of these lamp assemblies permits the use of circuitboards with different thicknesses ranging from .062 to .125 inch,depending upon the application. Other assemblies can be used to expandthis range depending upon the particular requirement.

When the pin connectors 14 and 16 are inserted into the mating sockets28 and 30, the connectors elongate and twist as the wire strands ofwhich they are comprised are abuttingly compressed within the walls ofthe sockets. Insertion of the lamp assembly connectors is limited by theabutment of the bottom surface 31 of collar 22 against the top surface33 of the portion of printed circuit board 25 which surrounds sockets 28and 30, as best viewed in FIGURE 4. Tight spring-tensioned electricalcontact between each of the connectors and its mating socket ismaintained along seven spiral lines corresponding to the outer strandsof the twisted wire comprising the connectors.

In another form of this invention, shown in FIGURE 6, a vertical typepair of lamp assemblies, as previously described and with like numeralsdesignating like parts, is encompassed by a single insulator collar 32having an interior hollow shape complementary with both assemblies,instead of each lamp assembly having a separate collar. The sockets forthese connectors are located in the circuit (not shown) into which theselamp assemblies are to be inserted, to provide a suitable matingengagement therewith. The collar 32, like collar 22, encompasses thesleeves and overlappingly extends from an intermediate portion of theenvelope 10 to an intermediate portion of the connectors 14 and 16,which limits their insertion in the sockets.

In still another form of this invention, as shown in FIGURES 7, 8, 9 and10, the lamp assemblies are of the horizontal type. That is, these lampassemblies are comprised of the same basic components (which carry likeprime numbers) as previously described, but the axes of the pinconnectors 14 and 16 are perpendicular to the axis of the miniature lampenvelope 10 instead of axially parallel to a common line, as in thevertical type of lamp assembly.

Thus, when the pin connectors 14 and 16 of a horizontal type lampassembly, as in FIGURES 9 and 10, are inserted in the complementarymating plated through holes 28' and 30 of a printed circuit board 25,the envelope 10' thereof lies flat adjacent to the top surface 33' ofthe circuit board 25', with its axis substantially parallel with theplane of the circuit board. In this form the long, tubular sleeves 18and 20 are eliminated to allow for the turning of the filament wires 12aand 12b between their entry into the envelope 10' and their attachmentto the pin connectors 14 and 16, respectively.

To secure the operative components of a horizontal type lamp assembly inposition, a specially shaped hollow insulator collar 34 is utilized.This collar 34 is generally oblong and formed with a longitudinal,rounded, internal configuration conforming roughly to the shape of theenvelope 10' contained therein. The top surface of collar 34 bulges inconformity with the shape of envelope 10', and the bottom surface 34a isfiat so as to correspond with the flat top surface 33' of a printedcircuit board 25' against which it is to lie. An opening or translucentportion of collar 34 adjacent to the envelope 10' permits the internalillumination to shine through.

On opposed sides of the collar 34 rounded ear portions 35 and 36 areformed. These ear portions 35 and 36 are each provided with bores 38 and39 respectively which communicate with the interior of the collar 34 andextend normal to the longitudinal axis of the collar 34. Extendinginwardly from flat surface 34a of collar 34 and communicating with bores38 and 39 are reduced bores 39a and 39b forming annular shoulders orstop means 40 and 40a.

These shoulders 40 and 40a serve as stop means for sleeves 41 and 42which are seated in bores 38 and 39. The sleeves are formed with crimps41a and 42a for retaining the pins 14' and 16'. Additionally a pottingcompound may be used to secure the sleeves 41 and 42 in position in thebores 38 and 39.

Another embodiment of the horizontal type lamp assemblies is illustratedin FIGURES 7 and 8. Here they are being used to illuminate the cornersof an annunciator assembly 44 which includes a plated circuit 44a. Thus,instead of one illuminating envelope per lamp assembly, a pair ofminature lamps 45 and 46, which are axially disposed in the same planebut aligned normal to each other, are included in each lamp assembly.

An open-ended L-shaped collar 48, with an internally hollowedconfiguration adapted to conform at each end to the external periphery,surrounds each of the envelopes 45 and 46. It supports these envelopesin position so that their bulb-shaped filament illuminating endsprotrude from the open ends of the collar 48.

A pair of tubular holes extends normally through a. central bottomportion of the collar 48. Mounted within these holes is a pair ofcomplementary sleeves 50 and 52, within which a pair of elongatedcomplementary pin connectors 54 and 56 is secured. The pin connectorsare the type previously described.

These pin connectors 54 and 56 protrude through the flat bottom surfaceof the collar 48 and are inserted into the mating plated through holesin the annunicator circuit board 44 to secure the lamp assembly in placeand serve as the common electrical contacts for both envelopes 45 and46. That is, filament wire 64a from envelope 45 and filament wire 66afrom envelope 46, extend through collar 48 to become attached to pinconnector 54, and filament 'wire 64b from envelope 45 and filament wire66b from envelope 46 extend through collar 48 to become attached to pinconnector 56.

The microminiature lamp assemblies can be assembled singly or inclusters. In the latter case, the reduction in the size of the socketspermits a greater density of lamps than was heretofore possible. Alsothe lights, depending upon the circuit board configuration and/or lampassembly utilized, may be arranged in series or parallel.

Although I have herein shown and described my invention in what I haveconceived to be the most practical and preferred embodiment, it isrecognized that departures may be made therefrom within the scope of myinvention, which is not to be limited to the details disclosed hereinbut is to be accorded the full scope of the claims so as to embrace anyand all equivalent structures and devices.

What is claimed is:

1. A microminiature lamp assembly comprising: a sealed, transparentenvelope; an illuminating filament contained within said envelope andadapted to be electrically energized; a pair of axially parallel,elongated, rigid, spaced, electrical pin connectors comprised ofresiliently compressible, helically wound strands of wire; a pair offilament wires extending from said filament through said envelope andpermanently secured with said pin connectors; a pair of tubular sleeveseach formed complementary with and crimped around a portion of each ofsaid pin connectors adjacent said filament wire securements; and arigid, hollow, translucent insulating collar encomprassing a portion ofsaid envelope and extending outward therefrom and encompassing anintermediate point of said pin connectors and completely surroundingsaid filament wires and said sleeves, said collar being internallyformed complementary with the encompassed portion of said envelope andthe encompassed portions of said tubular sleeves, whereby saidelectrical pin connectors are adapted to engage a source of electricityand energize said illuminatin filament.

2. A microminiature lamp assembly as defined in claim 1, wherein saidsleeves surround each of said filament wires protruding therefrom, saidenevelope is clongated and axially aligned parallel with theextendedaxes of said electrical pin connector and said sleeves, said collar istubular and the encompassing complementary portions of said collar areformed with internal shoulders abutting the termination of said sleevesremote from said envelope and said portions are reduced in diametercomplementary with said electrical pin connectors from said shoulders toend of said collar remote from said envelope.

3. A microminiature lamp assembly as defined in claim 2, wherein thespaces between said collar and the encompassed portions of said lampassembly are filled with a potting compound sealant.

4. A microminiature lamp assembly as defined in claim 1, wherein aplurality of said lamp assemblies is encompassed by a common collar.

5. A microminiature lamp assembly as defined in claim 1, wherein theenvelope is elongated and axially perpen dicular with the axes of saidelectrical pin connectors, an

interior portion of the collar substantially conforms to the shape ofsaid envelope and is formed with a pair of opposed hollow ear portionslaterally protruding from said collar and communicating with theinterior of said collar, said ear portions each has a tubular borecomplementary in size with the exterior of the sleeves and extendingnormal to the axis of the collar and axially parallel with each other,said envelope is mounted within said conforming portion of the collar,said pair of sleeves with the pair of electrical pin connectors fixedlysecured therein are mounted within the tubular bores so that theelectrical pin connectors protrude therefrom, and stop means in saidbores to arrest outward axial movement of said electrical pinconnectors.

6. A microminiature lamp assembly as defined in claim 1, which includestwo elongated illuminating envelopes with their axes disposed in thesame plane perpendicular to each other and the axes of the pair ofelectrical pin connectors are parallel with each other and perpendicularto the plane of said envelope, the filaments in said envelope arefixedly electrically connected by filament wires to said electrical pinconnectors as common electrical contacts, the collar is L-shaped andformed with a hollow interior having openings at each end complementarywith the external periphery of said envelopes within which saidenvelopes are mounted to protrude therefrom, and said collar has a pairof axially parallel holes extending through an intermediate portionthereof perpendicular with the plane of said collar and complementary insize with the external periphery of the sleeves within which said pinconnectors are secured, and said sleeves are mounted in said holes sothat the electrical pin connectors secured therein protrude from saidcollar.

7. A microminiature lamp assembly comprising: a sealed illuminatingenvelope; a light emitting filament carried within said envelope; a pairof adjacent, axially rigid and parallel spaced pin connectors, eachcomprised of a plurality of twisted wire strands adapted to beresiliently compressed and elongated when inserted in complementaryelectrical contact sockets, thereby providing tensioned spiral contactstherein; a pair of filament wires electrically connected with theopposite sides of said filament in said envelope, said filament wiresextending through said envelope and permanently affixed to said pinconnectors, thereby completing an electrical circuit through saidfilament when inserted in a pair of electrically energized contactsockets; and a rigid tubular support base encompassing said filamentwires and overlappingly secured to the connected portions of saidenvelope and said pin connectors, and wherein the rigid tubular supportbase is a hollow collar surrounding said filament wires, sai-d collar isformed with an interior end portion conforming to the connected exteriorend portion of the envelope for mounting said envelope, and includes apair of cylindrical counterbores communicating with said interior endportion and which conform with the external shape of said pin connectorswithin which said pin connectors are mounted to protrude from saidcollar.

8. A microminiature lamp assembly comprising: a sealed, translucentilluminating envelope, a filament contained within said envelope,elongated pin connectors of the type which are formed of helically woundstrands of wire adapted to resiliently compress when inserted incomplementary mating plated through circuit board holes, circuit meansconnecting said filament and said pin connectors, a hollow insulatorcollar surrounding said circuit means and secured to said envelope andto said pin connectors, wherein said filament, circuit means, and pinconnectors are made of electrically conductive material, and whereinencompassing complementary sleeves are permanently crimped to said pinconnectors and, in turn, are secured in complementary holes formed insaid collar.

(References on following page) 3,465,197 7 References Cited UNITEDSTATES PATENTS 8 OTHER REFERENCES IBM Technical Disclosure Bulletin, R.I. Keller and 10 193 .Reichel 313 31 X R. F. Spaniel, vol. 7, N0. 5,October 1964.

9/1961 Rafter 313318 X 11 19 1 Steal-n8 at a]. 74 72 5 JOHN W. HUCKERT,Pnmary Examlner 11/ 1966 Dinkler et 313318 X ANDREW J. JAMES, AssistantExaminer 11/1966 Ahroni 313-318 X US. Cl. X.R.

FOREIGN PATENTS 2/1954 Germany. 2/ 1959 Italy.

